After about three decades of development, the polyol process is now widely recognized and practised as a unique soft chemical method for the preparation of a large variety of nanoparticles which can be used in important technological fields. It offers many advantages: low cost, ease of use and, very importantly, already proven scalability for industrial applications. Among the different classes of inorganic nanoparticles which can be prepared in liquid polyols, metals were the first reported. This review aims to give a comprehensive account of the strategies used to prepare monometallic nanoparticles and multimetallic materials with tailored size and shape. As regards monometallic materials, while the preparation of noble as well as ferromagnetic metals is now clearly established, the scope of the polyol process has been extended to the preparation of more electropositive metals, such as post-transition metals and semi-metals. The potential of this method is also clearly displayed for the preparation of alloys, intermetallics and core-shell nanostructures with a very large diversity of compositions and architectures.

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has been considered as a potential anticancer agent owing to its selectivity for malignant cells. However, its clinical use remains limited because of its poor efficacy. Attempts to increase its antitumor activity include, among others, its functionalization by nanoparticles (NPs). In the present study, TRAIL was grafted onto magnetic spinel iron oxide NPs of defined core size, 10 and 100 nm on average, to see whether the size of the resulting nanovectors, NV10 and NV100, respectively, might affect TRAIL efficacy and selectivity. Apoptosis induced by NV10 and NV100 was higher than by TRAIL alone in both HCT116 and HepG2 cells. At equimolar concentrations, neither the nanovectors nor the corresponding NPs displayed cytotoxicity towards normal primary hepatocytes or TRAIL receptor-deficient HCT116 cells. NV100 exhibited superior proapoptotic activity than NV10, as evidenced by methylene blue and annexin V staining. Consistently, both caspase activation and TRAIL deathinduced signaling complex formation, as assessed by immunoblot analysis, were found to be increased in cells treated with NV100 as compared with NV10 or TRAIL alone. These results suggest that the size of NPs is important when TRAIL is vectorized for cancer therapy.

Polyol made from about 10 nm sized maghemite nanoparticles was functionalized by a hydrophilic catechol derivative, namely, dopamine. Infrared spectroscopy confirmed the grafting, whereas X-ray diffraction and transmission electron microscopy did not show either structural or microstructural change on the iron oxide particles. 57Fe Mössbauer spectrometry allowed, giving a quantitative assessment of the bonding preferences of dopamine on the iron oxide surfaces, the π-donor character of this ligand to be experimentally evidenced for the first time. These results are supplemented by ab initio modeling, expanding on previous work by considering various iron oxide surfaces and orientations. Perspectives of the work are discussed.

We propose the elaboration and study of rheological properties under continuous magnetic field of magnetic sensitive biopolymer-based nanocomposites. Magnetic iron oxide (maghemite) nanoparticles were synthesized by the polyol process and then functionalized by grafting organic bifunctional ligand for establishing electrostatic bonds between the sodium alginate chains of biopolymer and functionalized nanoparticles. The enhancement of rheological properties at low shear rate of these new magnetic soft nanocomposites was clearly demonstrated by the increase of yield stress and viscoelastic moduli in the linear viscoelastic domain with an increase of applied magnetic field, thus providing new functionality to these soft nanocomposites.

The removal of radio-elements, notably uranium, from wastewaters is crucial for public health and environmental remediation.

Human serum albumin (HSA), the most abundant plasma protein in human blood, is a natural transport vehicle with multiple ligand binding sites.

Self-assembled enzyme aggregates, prepared from magnetic iron oxide nanoparticles, avidin, and a biotinylated redox enzyme, were shown particularly useful for the simple, fast, and efficient construction of highly enzyme-loaded electrodes with the help of a magnet. The approach was illustrated in the case of the bioelectrocatalytic oxidation of NADH by a diaphorase oxidoreductase in the presence of a ferrocene mediator. Two different self-assembling procedures were tested, taking advantage of the spontaneous aggregation of the nanoparticles in the presence of avidin and also of the multivalency binding of biotinylated diaphorase toward avidin. Activities of the bound and unbound diaphorase were systematically controlled allowing determination of the number of active biotinylated diaphorase per nanoparticle incorporated within each magnetic enzyme aggregate. An active enzyme loading capacity of up to 2.35 nmol mg-1 was found for the best nanostructured enzyme assembly, which is 200 times better than for commercialized magnetic micrometer-sized beads coated with streptavidin and saturated with diaphorase. With the help of a permanent magnet, the magnetic enzyme aggregates were finally magnetically collected as a film on the surface of a small screen-printed carbon electrode and the catalytic currents recorded by cyclic voltammetry. From the analysis of the steady-state catalytic current responses and the kinetic rate constants of biotinylated diaphorase, it was possible to determine the enzyme concentration within the magnetic films. Owing to the high enzyme loading in the aggregates of nanoparticles (i.e., 130 microM), the catalytic current responses were definitely higher than the ones measured at an electrode coated with a closed-packed monolayer of diaphorase or at an electrode covered with a film of magnetic micrometer-sized streptavidin beads saturated with diaphorase.

Using solar radiation to fuel catalytic processes is often regarded as the solution to our energy needs. However, developing effective photocatalysts that are active under visible light has proven to be difficult, often due to the toxicity, instability, and high cost of suitable catalysts. We engineered a novel photoactive nanomaterial obtained by the spontaneous electrostatic coupling of carbon nanodots with [P2W18O62]6–, a molecular catalyst belonging to the class of polyoxometalates. While the former are used as photosensitizers, the latter was chosen for its ability to catalyze reductive reactions such as dye decomposition and water splitting. We find the electron transfer within the nanohybrid to be so efficient that a charge-separated state is formed within 120 fs from photon absorption. These results are a cornerstone in the engineering of a new class of nanodevices, which are nontoxic, are inexpensive, and can carry out solar-driven catalytic processes.